\begin{tikzpicture}

\definecolor{darkgray176}{RGB}{176,176,176}

\begin{axis}[
tick align=outside,
tick pos=left,
x grid style={darkgray176},
xmin=0.5, xmax=2.5,
xtick style={color=black},
y grid style={darkgray176},
ymin=0.5, ymax=2.5,
ytick style={color=black}
]
\path [draw=red, line width=0.48pt, dash pattern=on 4.44pt off 1.92pt]
(axis cs:1,1)
--(axis cs:1,2)
--(axis cs:2,2)
--(axis cs:2,1)
--cycle;

\end{axis}

\end{tikzpicture}
